Unusual Ferrite Induced Photohydrolysis of Dinitrophenols to Nonaromatic and Nontoxic Derivatives

Zinc ferrites can induce the photodegradation of many organic pollutants. Here ZnFe2O4 has been used as a catalyst to photocatalytically degrade 2,4-dinitrophenol (2,4-DNP). Using GS-MS, an unusual ferrite induced photohydrolysis of aromatic moiety of dinitrophenols was observed. At least two new compounds, 6-hydroxy-3,5-dinitrohexa-2,4-dienal and 4,6-dinitrocyclohexa-3,5-diene-1,3-diol, were unambiguously identified by GC-MS, which resulted by the addition of one or two molecules of water, with the corresponding disappearance of uncoupling properties of the parent 2,4-DNP. The photochemical mechanism of 2,4-DNP degradation was investigated and OH center dot radical generation using isopropyl alcohol and terephthalic acid test was demonstrated. Additionally, only 5 min of irradiation in the presence of ZnFe2O4 may be enough for the degradation of very hazardous compounds to inoffensive ones, and it may afford nonaromatic derivatives. The germination experiments, using the supernatant obtained after 2,4-DNP photodegradation, show the total lack of toxicity on wheat seeds and seedling. Thus, the 10(-3) M 2,4-DNP solution inhibited wheat germination and produced no seedlings, while the average height of the shoots resulted from the supernatant-treated seeds was 8.48 +/- 0.84 cm, higher than 7.51 +/- 0.92 cm in the H2O-treated control samples. The obtained results suggest a great potential for application of the ZnFe2O4 for solving some environmental problems.